Jailbreak

Cydia

MuscleNerd announced last night that the he has successfully ported the Monte untether to use iOS 4.1 blobs. This means that there is no need to burn an exploit to jailbreak iOS 4.2.1, and that the new greenpois0n previewed by Chronic Dev might be held in reserve. It also resolves ongoing concerns about SHSH piracy that have created controversy in the jailbreak community.

The "Jailbreak Monte" method is a way to recycle exploits by convincing the device that it's running a given firmware right up to the pwnage step, then switching to the newer firmware thereafter. Currently, you need to have an iOS 4.2b3 SHSH blob - which only people in the developer program legitimately have access to - in order to jailbreak 4.2.1 untethered using Monte. When the next version of redsn0w is released, you'll only need iOS 4.1 SHSH blobs, which redsn0w will fetch for you whether or not you'd backed yours up: Apple is still giving those to everyone from their servers. EDIT 01/23/11: Note: Apple is NOT actually giving out 4.1 blobs anymore.

Encouragingly, MuscleNerd says that Monte is a lot more versatile than even he had though, noting that he "had seriously overcomplicated things before today." The team is currently working on porting Monte forward to 4.3, which would make "ultra-recycle" even more green than it is today.